Organ pedal light trigger

[rabbithole1243]

Hi there – I’m currently working on making a simple MIDI organ pedal by using the parts from an old Casio keyboard hooked up to a set of Hammond organ pedals.

I’d like to give this project a little aesthetic appeal…what I’m envisioning is using a plexiglass top on my pedal board casing so the ‘guts’ can be seen. No problem there. However, I’d like to have a light be triggered inside the casing when a midi note is triggered. I’d be satisfied if it were a single light or a set of lights. I’m thinking about using a small lightbulb rather than an LED - something that can be seen from the crowd but not be too distracting.

Would anyone know how I might do this?

[lylehaze]

regular lightbulbs have a “inrush current” when turned on that is many times the normal current load.

Consider LEDs  instead of lightbulbs to avoid this problem.

I’ll leave the MBox details to someone who has more experience.

Have Fun,

LyleHaze

[rabbithole1243]

Thanks for the tip. But don’t hold back from the details - that’s what I’m here for. The lightbulb was an initial idea but LEDs are fine.

[clem]

Hi,

if you want to switch 230 or 110 Volts you can use a relay and control it via Dout. (–> don´t  do it without any electronical skills - it can kill you!)

If you want to witch 5V you don´t need any relay because the Dout offers this.

I don´t know if there´s still a midibox application that controls a simply Mid-Data-In_LED but I think it will be a simple extension of three to ten rows in the code to realize a blinking LED.

But wouldn´t this be a little bit boring for the mb - why not take multiple LEDs and program different light patterns for different midi notes and create the “MIDIbox Shining”  ;)

Best regards,

clem!

[lylehaze]

I didn’t “hold back” as a tease, it’s just that I have not written that particular app, so I was leaving the comment space to someone who has. Lately I have been more hardware anyway, so I wanted to cover that detail.

Many folks don’t know about “inrush current”, and they build a driver for a light bulb that is just enough to handle the normal current for the bulb.. then they get disappointed when it goes “poof”.

Clem added great details:

Most Midibox applications use a DOUT board for digital (on/off) outputs.

a DOUT output can drive electronics, or an LED, without any additional help.

There are chips we use with DOUTS to get a stronger signal for LED matrixes (ULNxxx?)

If you want to drive something much bigger, look into either a relay, or a “solid state relay” that has an LED as it’s input. At that point you could be switching entire strings of Christmas lights (by MIDI!) or your coffeepot, or the motorized electric shades you put on your windows.

What I do NOT have personal experience with is exactly how to set MIOS up to drive your DOUT from a note ON/note OFF message. I know it’s possible, and I’ll bet it’s not difficult, but I will let someone with more detailed experience answer that for you.

A DOUT board supports 32 outputs, so you’ll have lots of room to expand your ideas.

Take a look in the WIKI and the uCapps site. Look over the schematics for a core and a DOUT board, and decide whether you want to build them from scratch or buy kits. Look over some existing projects, maybe the MIDIO128 would be a good start.(I’m guessing) Then figure out what you can do with 32 LEDs that are individually driven by MIDI.

Part of the “fun” is learning a bit of electronics and a bit of programming to realize your project.

No Fear! It’s all about making dreams come true.

Have Fun,

LyleHaze

[nILS]

If you want to drive multiple LEDs from a single DOUT pin relays or transistor drivers may be your friend. A forum search will give you some hints (ULN2803 might be a good place to start).

As for the app, something as simple as this will already do:

/////////////////////////////////////////////////////////////////////////////
//  This function is called by MIOS when a complete MIDI event has been received
/////////////////////////////////////////////////////////////////////////////
void MPROC_NotifyReceivedEvnt(unsigned char evnt0, unsigned char evnt1, unsigned char evnt2) __wparam {
// note event
if ((evnt0 == 0x90) && (evnt2 > 0)) // note on
MIOS_DOUT_PinSet1(evnt1);
else
if ((evnt0 == 0x90) || (evnt0 == 0x80)) // note off
MIOS_DOUT_PinSet0(evnt1);
}[/code]





(From the top of my head, untested)

[mikee]

casio keyboard parts, hammond pedals and a lamp driven from midi?

where’s the midibox stuff?

Are you simply trying to make a lamp flash on and off when a pedal is pressed? that only requires a 12v 2.5w car lamp (Halfords or any car parts shop) a couple of transistors, and a few bits n pieces.

The midi output (before the opto isolator) will drive the thing. See attatchment (The transistors are not critical, as long as they are NPN.)

regards

oops, just realised— MIDI too fast, lamp too slow. You really need to stretch the MIDI pulses, perhaps a 555 timer or something.

If all else fails get youself a pet monkey and train it to flash a torch as you pedal away.

regards again.